Is USB a digital signal

[rbhawcroft]

I think it is but I keep reading snippets about its Ananlog TX and RX units inside transceiver chips, can anyone clarify what this refers to? I'd be very grateful.

 

[Drekce]

USB is digital, as is serial, paralell, etc. An analog voltage must be sent over the Rx and Tx lines, but this is how the digital values are understood by electronic components. Usually a voltage of +5V signifies a digital 1, and a voltage of 0V is a 0. (These arent exact, but usually within a range (>2.5V = 1 , < 2V = 0). For a serial port it actually uses 12V signals to transmit the digital data.

 

[sohcrates]

Yeah, what he said

Basically, it *is* digital...but you have to remember that it also provides POWER to the connected devices, so in that case it's not like a pure digital cable.

 

[rbhawcroft]

ok thanks. I was looking at data sheets. and it was a bit confusing! I thought that the data was digital but couldnt figure out the analog blocks! thanks again.